Evaluation of rice genotypes for sugarcane borer resistance using phenotypic methods and molecular markers

This study aimed to observe the response of 34 rice accessions to attack by sugarcane borer (Diatraea saccharalis Fabr., 1794) and to analyze the genetic diversity of these accessions by microsatellite markers. Twenty larvae were placed on the leaf sheaths of rice plants. At 30 days after infestation the rice plants at ground level were taken to the laboratory where the signs of borer attack, external and internal diameter of the stem and weight of surviving larvae were determined. For the molecular analysis of rice accessions, 24 microsatellite markers were used. The results of the morphological traits of the rice plant, response of the plant to insect attack, development of the sugarcane borer larvae and molecular data, indicated a genotypic variation. The accessions that most favored larval survival were IAC 47 and Ti Ho Hung. Larvae with highest weight (0.0986 g and 0.0862 g) and the largest internal diameters of the rice stem (3.18 mm) were found in land races “Canela de Ferro” (rust colored stem) and all these “Canela de Ferro” accessions also remained genetically grouped. The most tolerant materials, based on the ability to produce new tillers after larval infestation were, Chiang an Tsao Pai Ku and IR 40 which remained morphological and genetically grouped. The results of this study indicate that all the traits and molecular analyses were able to separate the accessions of rice into different groups in relation to resistance to the sugarcane borer. These materials can be used as donor sources in breeding for genetic resistance to sugarcane borers and can be used as donors to amplify the genetic base of Brazilian rice.